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| Self-Sterilizing Fixtures in Public Buildings | C. W. Vermeulen5, Katherine E. Pouns1, David A. Garcia2, Miki C. Duruz3, Kara L. Morgenstern3, Clara C. Watkins5, Chester L. Duckworth5, A. Frank Gerdin5, Michael I. Cogan4, Benjamin G. Conner4, Stephanie G. Lanier4, Alexander J. Spirn4, Javon Uzzell4, Jennifer N. West4, and E. Sherman Belcher5 (1) Second Baptist High School, Houston, TX; (2) Va. Commonwealth Univ., Richmond, VA; (3) Long Beach Senior High School, Long Beach, LI, NY; (4) Jamestown High School, Williamsburg, VA; (5) Science-Projects.Com, Williamsburg, VA (ecoligist@yahoo.com) |
| As presented to the Amer. Soc. for Microbiology 07 June 2005 Atlanta, GA |
Schools, public buildings and transport are major centers for the spreading of common diseases, costing nations greatly in lost productivity. We thought it possible to make rapidly self-sterilizing surfaces for frequently handled railings, push-plates, and desktops by the addition of antimicrobial agents that are non-volatile, stable, inexpensive and non-toxic to people. Into clear, highly durable varnishes, furniture and floor polishes were mixed dusts of coinage metals and their salts, SDS and quaternary ammonium salts (QAS). The dried coatings were contaminated by hands moistened with a garden soil slurry, and then assayed at timed intervals to ascertain the die-off rates of the applied mixed microbes. Coloration, texture and durability were also noted.
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Specifics: One week old varnish and polyurethane doped with at least either 25% Cu (I and II) chloride or 2% QAS's were found to self-sterilize within seconds of handling. The effect deteriorated to only 30 seconds after five months. Doped polishes took over 15 minutes to self-sterilize. The moderately effective salts of lead, mercury, chromium and silver were excluded for human toxicity or cost. Copper chloride was judged only marginally acceptable as it added color to the coating and had a coarse touch due to its not being soluble in the coatings. QAS's were soluble, added no coloration, and did not become slippery from moist hands. Heat stable colloidal silver is costly but may be the candidate of choice for adding to molten plastics such as those being formed into the handles of serving spoons in self-service restaurant buffets.
"Science-Projects.com" encourages students, teachers and retirees to work collaboratively on original projects with an aim toward making presentations beyond science fair. This is the sixth presentation at the ASM made under this logo. The website is owned and operated by Dr. Vermeulen, emeritus microbiologist from the College of William and Mary in Williamsburg, Virginia.